feat: Add GetCoordAt()

coord.go

@@ -86,6 +86,11 @@ func (c Coord) GetCoordsAround() Coords {
 	}
 }
 
+// GetCoordAt returns the coord at the given offset from the current coord.
+func (c Coord) GetCoordAt(xOffset, yOffset int) Coord {
+	return Coord{c.X + xOffset, c.Y + yOffset}
+}
+
 // Coords is an array of coordinates.
 type Coords []Coord
 

coord_test.go

@@ -187,3 +187,91 @@ func Test_Coord_ConnectsTo(t *testing.T) {
 		}
 	})
 }
+
+func Test_Coord_GetCoordAt(t *testing.T) {
+	base := Coord{1, 1}
+	type input struct {
+		xOffset int
+		yOffset int
+	}
+	testCases := []struct {
+		description string
+		input       input
+		expected    Coord
+	}{
+		{
+			description: "works top",
+			input: input{
+				xOffset: 0,
+				yOffset: 1,
+			},
+			expected: Coord{1, 2},
+		},
+		{
+			description: "works top right",
+			input: input{
+				xOffset: 1,
+				yOffset: 1,
+			},
+			expected: Coord{2, 2},
+		},
+		{
+			description: "works right",
+			input: input{
+				xOffset: 1,
+				yOffset: 0,
+			},
+			expected: Coord{2, 1},
+		},
+		{
+			description: "works bot right",
+			input: input{
+				xOffset: 1,
+				yOffset: -1,
+			},
+			expected: Coord{2, 0},
+		},
+		{
+			description: "works bot",
+			input: input{
+				xOffset: 0,
+				yOffset: -1,
+			},
+			expected: Coord{1, 0},
+		},
+		{
+			description: "works bot left",
+			input: input{
+				xOffset: -1,
+				yOffset: -1,
+			},
+			expected: Coord{0, 0},
+		},
+		{
+			description: "works left",
+			input: input{
+				xOffset: -1,
+				yOffset: 0,
+			},
+			expected: Coord{0, 1},
+		},
+		{
+			description: "works top left",
+			input: input{
+				xOffset: -1,
+				yOffset: 1,
+			},
+			expected: Coord{0, 2},
+		},
+	}
+
+	Convey("Coord.GetCoordAt()", t, func() {
+		for i, tc := range testCases {
+			Convey(fmt.Sprintf("%d: %s", i, tc.description), func() {
+				res := base.GetCoordAt(tc.input.xOffset, tc.input.yOffset)
+
+				So(res, ShouldResemble, tc.expected)
+			})
+		}
+	})
+}

render.go

@@ -25,7 +25,7 @@ func GetRender(s *Surface) string {
 
 	rowVals := make([]string, 0, len(rows))
 	for i, row := range rows {
-		row = append([]string{fmt.Sprintf("%01d | ", s.height-i-1)}, row...)
+		row = append([]string{fmt.Sprintf("%02d | ", s.height-i-1)}, row...)
 		rowVals = append(rowVals, strings.Join(row, " "))
 	}